


Step One

by tuesday



Category: Iron Man (Movies), Marvel Cinematic Universe, Spider-Man (Tom Holland Movies)
Genre: Adult Peter Parker, Alpha/Beta/Omega Dynamics, Alpha/Omega, Dubious Consent, Explicit Sexual Content, M/M, Mating Cycles/In Heat, Outer Space, POV Third Person, POV Tony Stark, Past Tense, Stranded, trapped together
Language: English
Status: Completed
Published: 2019-04-27
Updated: 2019-04-27
Packaged: 2020-01-13 04:11:39
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,600
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18461219
Author URL: https://archiveofourown.org/users/tuesday/pseuds/tuesday
Summary: "You have got to stop following me onto spaceships, kid."





	Step One

**Author's Note:**

  * For [floweringbloom](https://archiveofourown.org/users/floweringbloom/gifts).



> This is a treat for smut swap, a fic exchange. 
> 
> Recip, I went with the "A/B/O - Secret Omega Goes Into Heat" tag and the prompt, "Are they trapped together when one of them goes into heat/rut?" What could be more trapped together than in space? I tried to work in some of your other likes, too.
> 
> This is set an unspecified time after IW, with brief references to it at the beginning. It presumes that everything is fixed and everyone is alive. I'm reading/writing Peter as at least eighteen, but also leaving it vague enough to let anyone else do what they want. 
> 
> Thank you to Duck and to LF for letting me ramble at them about this. Also, I have another a/b/o fic I wrote for this prompt, but I decided it didn't fit closely enough, so expect that soon.
> 
> Redating for author reveals. Sorry if anyone sees this twice! (And, uh, about suddenly having All the Fic at once; I wrote four fic for this exchange, plus posted two recently, plus one more that's coming soon.) This is not Endgame compliant, as it was written for an exchange with a due date prior to Endgame's release.
> 
> Content advisories are in the end notes.

"You have got to stop following me onto spaceships, kid." Tony rubbed a hand against his face, feeling every one of his years.

"It's worked out for me so far," Peter said, which … was definitely not the case. Peter got that stubborn look on his face he always did whenever Thanos came up and said, "Hey, at least I got the chance to fight for my life. That's better than almost anyone else did."

Tony sighed. "Can we talk about literally anything else?"

"Sure. Do you want to focus on the fact that we're trapped on a ship headed who knows where with no food left, limited water, and no way to turn it around? Do you want to talk about the fact that the controls are locked and in a language we don't speak and can't read? Do you want to talk about the fact that neither of us does well when faced with space anymore, and we are currently stranded in the middle of it? What would you like to talk about, Tony? I'm up for anything." From the way Peter was pacing in the confines of the cockpit, he really was not up for anything.

Tony stared out at the stars. "Why did you follow me up here?"

"I wasn't about to let you face it alone."

Tony tipped his head back to stare at the bulkhead. "It would have been better if you had. For both of us."

"Oh, yeah, you'd have six days of water left instead of two. That's much better. Or maybe that guy would have killed you, and then you wouldn't have to worry about the water situation at all." Peter stopped, took a deep breath. "Sorry. I don't know why I'm so—" He ran a hand through his hair. "Sorry."

"See, I do know why you're so irritable." Tony tapped his fingers against the nanite housing, not activating anything, just a nervous drum to bleed off excess energy. "Which is the same reason it would be better if you weren't trapped in here with me." He blew out another breath, wishing he could get some fresh air right about now. "When's the last time you took your suppressants?"

"Um." Tony watched Peter do the math in his head. "I'm about due, but not yet."

"High stress situations make you burn through them faster. And I don't mean the general you, here, Peter—your metabolism kicks into overdrive when you're fighting and when you're upset." Tony's lips quirked up into a humorless smile. "That was a hard fight, even if we won, and I'd say the couple days we've tried and failed to turn this ship around have been very, very stressful for the both of us."

"Just being off suppressants wouldn't be enough to send me into rut. In the absence of an omega—"

Tony held a hand up. "Going to stop you there. That absence is the opposite of a given."

Peter stared, which was flattering for Tony's ability to keep a secret even from those close to him. "You're—?"

"Yep."

"But I mean. Even if you're—" Peter fiddled with his gloves. "We could always both suit up?"

"The air scrubbers aren't that good. You'd have to go full hard suit, and the personal oxygen reserves were designed to last a couple hours, tops. Every time you refilled it, you'd be exposed to the scent of an omega in heat."

"In heat?" Peter asked in an adorably high voice.

"I was already overdue when some alien maniac decided to kidnap me." Tony scratched his beard. "Honestly, I'd planned to ride it out at home. I'm not getting any younger, and I thought, maybe. Well. Even if Pepper didn't want children when we were together, I don't need anyone else for that. Step one was going off suppressants and seeing if I had a normal heat." Tony rested his left elbow on the ledge of the console and his chin on his palm. He waved his right hand. "Surprise. Step one looks like it's going to be a success."

"You're going to have kids?" Peter's expression did not fit the seriousness of the situation at hand. He looked kind of like Christmas had come early and Tony had gotten him a brand new suit with jet boots. "That's awesome."

"No, I'm not, because we are about to die in space because I'm too distracted by my hormones and how amazing you smell to _fix this_ and get us home."

"If the problem is you're distracted," Peter fiddled with his gloves again, "maybe we should give you what you want."

"That's a terrible idea," Tony said, even as part of him sat up and said, _Yes, please_.

"Then what's your solution?"

Tony shrugged one shoulder. His laugh was bitter, because even now, after years of Tony proving himself fallible over and over again, Peter still believed in him. "I don't have one."

Peter swallowed. He lifted his chin. "So if you have no answers, my answer is to take advantage of the resource currently available to you—"

'Take advantage of' was definitely the right wording there, Tony thought, though Peter was far more to him than a resource.

"—and time and biology are going to force our hands either way, why not make it easy on ourselves and maybe get a little more work done while we're still capable of thinking clearly?" Peter tapped at the spider emblem on his suit, causing it to draw back and fold in. He climbed into Tony's lap like he'd never doubted his welcome there. Tony's hands, the traitors, moved without his input to steady him. "I can get you off and maybe you can concentrate on what you're doing for more than five minutes at a time."

Tony was having a lot of trouble seeing the problem with that logic. He licked his dry lips. "I can't do this to you. I can't—I can't be the one who—" He leaned in, rested his forehead against Peter's. "I could wreck you, Peter. It's what I do."

"I heal fast." Peter slid his hands into Tony's hair. "Trust me to know what I can handle. Please."

Peter moved slowly. Tony had plenty of time to turn his head as Peter brought their lips together. He made a pained sound and didn't move. Peter licked at the seam of his mouth. He nipped at Tony's lower lip. He pressed kiss after kiss to Tony's unyielding mouth until Tony surrendered and softened his lip. Peter gave a happy hum and slipped his tongue inside Tony's mouth, slid their tongues together, soft and wet and sweet.

Tony's hands clenched at Peter's hips. Peter shifted, resettled himself so his weight was pressed against Tony's dick. Peter pulled back.

"What do you want?" Peter asked.

Tony laughed again, tinged with hysteria. "To go home."

Peter's voice was patient, all that irritation bled away with one little make-out session that wasn't even over yet. "What can I do for you?" He tugged gently at Tony's hair. "Tell me. What can I do?"

Tony gave up. "Whatever you want. I'll take whatever you want to give me."

Peter slid off of Tony's lap and pulled the pilot's seat around, its back to the console and the view of the stars. All Tony could see was the back wall and Peter kneeling on the floor. Peter undid Tony's jeans and drew his dick out of his underwear. Tony watched, heart in his throat, as Peter's lips wrapped around him, warm and wet and so, so good, everything he'd ever told himself not to want.

Tony hissed an obscenity as Peter took him all the way down, no hesitation, just jumping straight in. Peter's hands were moving, opening up his own pants and pushing them down his thighs. He moaned, loud and shameless, obviously enjoying himself.

"Wait, wait," Tony said. He tapped Peter on the forehead. "Off, a second."

Peter drew off with a popping sound that should have been silly, but Tony's hopeless dick found deeply sexy. "Did I do something wrong?"

"No. You're perfect." It was probably the truest thing Tony had ever said. Peter was perfect, and Tony really ought to be keeping his grubby hands to himself instead of dirtying him up a little. That ship had sailed—along with the pair of them deep into unknown space, navigation system refusing to give them any useful information to work with. "But if we're going to do this, we should do it right—or as close as we can get without a proper bed to spread you out on."

Tony stood and drew Peter up with him. "Come on. Clothes off."

Tony put words to action, shrugging off his jacket and ducking out of his shirt. They went on the copilot's seat, then his jeans, underwear, and socks. Peter dropped his own on the floor. When Tony was naked, he sat back in the pilot's seat, its weirdly leather-like texture sticking to his skin. It was a good thing this wasn't Tony's ship, because he was leaking from his dick and his hole both, probably voiding any sort of warranty. At the very least, it would be a pain to get his slick out of the cushion.

Peter shoved his clothes over to protect his knees and knelt between Tony's thighs again. This time, he started with a kiss to the inside of Tony's thigh, then pulled Tony forward, his ass all the way on the edge of the seat. Peter lifted Tony's thighs over his shoulders, casually arranging him exactly how Peter wanted him. Peter stroked Tony's inner thigh, then slid his fingers up, up, back to where Tony was aching and wet and desperately ready for him.

Tony's toes curled as Peter slid two fingers straight in, no prelude, and crooked them, moving methodically, searching out the right spot, until—

Tony couldn't help the cry pulled from his throat. Peter's eyes were half-lidded. His smile was sharp, satisfied. He rubbed over the same area again, like he wanted to be sure, then a third time maybe just because. He licked up the side of Tony's dick as he started sliding his fingers slowly in and out. Tony dug his hands into the arm rests. Peter added a third finger, and Tony rocked into it whenever Peter thrust back in.

"You look really good like this," Peter said quietly. "It's almost worth a one-way ticket to the middle of nowhere."

Tony tried to form words, but couldn't find them, lost track of his thoughts entirely when Peter closed his mouth over his dick. Peter's fingers filled him up. His mouth swallowed him down. The sounds Peter made were pleased, pleasing to Tony's ears. The scent of him was deepening, strengthening in the enclosed space, and Tony's own was rising up to meet it. The room smelled spicy now, musky and sweet. Tony breathed open-mouthed and tasted them on the air. He felt like he was suffocating, drowning in the scent of Peter, pheromones, and sex.

"Peter," Tony said. "Ah, Peter, I can't—" He didn't know what he was saying. "I need—" It was too much. It wasn't enough. "Peter, please."

Peter pulled the orgasm out of him like something stolen, bowling Tony over and taking it before he could catch his breath. Tony shuddered his way through it, wave after wave, and when he was done, Peter drew back, dropped Tony's thighs to around his waist, and replaced his fingers with his dick. Tony let his head fall back against the back of the chair and tried not to sob with how much he wanted it, how good it felt, how it was exactly what he needed.

Peter kissed Tony with salty lips. He pulled Tony out of the chair entirely, dragging them down. Tony's back hit the floor, his face tucked into Peter's neck, Peter cradling the back of his head with one hand. Peter's next thrust took them skidding forward an inch, forcing another breathless, "Ah!" out of Tony. Peter kept going, and it was perfect, perfect, perfect.

The next hour or so was messy, desperate, and terribly fun. None of it, of course, was conducive to actually fixing their situation. It was a nice way to take their minds off it, but in the end they were still hurtling through space, further and further from home.

Tony rested his head on Peter's shoulder. Peter was sitting in the pilot's chair this time. Tony was sitting on him. They were tied together and yes, oddly, Peter was right. It was easier to concentrate with Peter's dick in him. Tony was clear-headed enough to be perfectly aware of how utterly screwed they were.

"We're not getting any data because it's broken," Tony said. He tapped his finger against the display. "But the rest of it—yeah, we're still locked out of that."

"We'll figure it out," Peter said. He ran his fingers through Tony's hair.

"With what time?" Tony wasn't giving up, but he was feeling the pressure. Time was working against them in every possible way, and it was very quickly running out. "If you think I'm going to be capable of thinking about anything but how much I want your knot by this time tomorrow—" Tony shook his head.

"Um. I didn't want to get your hopes up," and Peter already looked like he was regretting talking, "but I did get a call out before I got on the ship."

"Unless you had a direct line to Nebula or Thor, not sure how much that's going to help us."

Peter's smile was slight, but there. "Yeah, kind of? I mean, not exactly, but I called Dr. Banner, and Thor was right there."

Tony sat up straight. "If they know where we are—"

"That's why I've been focused on the communications system," Peter explained. "I thought if we sent a distress signal, and they already have a general trajectory—"

"We don't have to get home; we just have to let them catch up with us." Tony kissed Peter full on the mouth. "Okay, forget nav and steering. We just need the radio and the brakes."

—

They fixed the radio and pumped the brakes. They didn't have steering, but it was in their best interests to stay where they were, distress signal running and friends on their way. In a fit of optimism, Tony had drawn back on his clothes in hopes they'd soon be needed. It probably would have been better to have left them off.

Peter had draped himself over Tony's back and was mouthing at the side of Tony's neck, biting and sucking and licking as Tony pushed his pants down to his knees with trembling hands. Peter didn't bother trying to stretch Tony this time, just bent him over the back of the chair and stuck it in, fucking straight into Tony in one smooth stroke. All the air punched out of him. Peter had gotten dressed, too, in the foolish hope that rescue would arrive before Tony's heat hit for real, and the metal of the open zipper's teeth bit into the back of Tony's thigh.

Peter's hands were bruising at Tony's hips. He moved his mouth to the back of Tony's neck and bit down. His hands, his teeth, and the weight of his body all held Tony in place. Tony had no choice but to stay there and take it as Peter drew back and slammed in again. It soothed something feral and needy in him, to be held close and held down. If it were someone else, maybe Tony would be concerned, but he trusted Peter, knew he'd never hurt him. The safest, best possible place for him was right here, letting Peter take what he wanted, letting Peter give Tony what he needed.

Tony whined high in the back of his throat. His body throbbed, aching and empty, when Peter drew back, and felt filled to bursting every time he sank back in. Tony's mouth kept running away with him, half-nonsense and on autopilot.

"Yeah, that's it. You're doing so well. Give it to me, just like that. You're so good, kid. You're perfect. That's perfect."

Peter dug his teeth in a little more firmly, and Tony felt himself getting a little wetter, felt himself _want_ a little more. The sounds their bodies made were obscene, and Tony needed it. He needed it so much. Tony involuntarily clenched down around Peter, and Peter's next thrust was even harder. Tony was pressed into the back of the chair so hard that he could feel the metal of the support under the soft cushioning.

"You're so—ah, that's just—oh, fuck. I can't—" Tony closed his eyes and shuddered his way through what was maybe his fifth orgasm of the day.

There were advantages to heats. Most of them were the same as the disadvantages. Everything was nicely hazy, his thoughts quiet, as he went limp and enjoyed the feeling of Peter as he fucked Tony through his orgasm, then kept going. He couldn't remember why he'd thought this was a bad idea. Peter was made for this, for him. Or maybe Tony was the one made for Peter, had been waiting for him this whole time.

Peter's knot caught on the rim of Tony, then pushed in with the next thrust. Tony clenched around Peter again, on purpose this time, drifting happily on endorphins and wanting desperately to give back. When Peter came, he half collapsed on top of Tony, crushing him into the chair's back. Tony reached back and patted at Peter's shoulder.

"Kind of getting squished here," Tony wheezed.

Peter mumbled something indistinct against Tony's neck, but he straightened up, and Tony could breathe again. Peter pulled them back to the floor, Tony in Peter's lap, back to chest, Peter's arms wrapped around him and face pressed into his shoulder. Tony's pants were around his ankles. He gave in to the inevitable and kicked them off. He pushed Peter's head away just long enough to get his shirt off, then pulled Peter back down with a hand in his hair.

"You smell so good," Peter said, nosing at Tony's skin. "You should stay off suppressants all the time."

"That was the plan," Tony agreed.

Tony could feel Peter's frown. "But you're going to need someone to help you with your heat."

"I, ah," Tony shivered as Peter shifted, "I had FRIDAY make a list of candidates for me to review, but—" Tony cut off as Peter licked the marks he'd left. "But—" Tony couldn't remember what he was talking about. "Stop teasing and bite me."

"I want to claim you," Peter said in a hushed voice, like a confession, like a shameful secret he'd never planned to share. "I want to keep you."

Tony's chest ached. He wanted it, too. "That's the hormones talking."

Peter's fingers trailed from Tony's neck, where he'd left his marks, down to the join of shoulder and neck, which he'd stayed away from so far. He rubbed the pads of his fingers over the slight bump where a bonding bite would go. Even the slight pressure against the gland had Tony's hands in fists, his toes curling, his hole clamping down around Peter's knot.

"A little bit," Peter agreed, "but I've always wanted you. Since I met you, I wanted you." He removed his hand and put his mouth back against Tony's neck, safer, but not where Tony wanted it most now that the idea had been introduced.

Tony swallowed down the words _You could_ and instead tipped his head back. Tony offered up a confession of his own. "I shouldn't, but I want you to keep me, too."

Peter made a pained noise. He worried gently at Tony's skin. He wrapped a hand around Tony's soft dick and stroked it, slow, loose movements. Tony wasn't ready to go again, but this was nice.

"Do you think they'll be here soon?" Peter asked. "It's—I mostly feel fine just the two of us, but I don't—I'm not sure—" Peter gave a sound of frustration. "I'm worried I might try to attack someone if they come in while we're both naked. My instincts are kind of all over the place here."

"I think we'll have enough warning to tell them to stay off the ship until we're both dressed." Tony reached a hand up to pet at Peter's hair. "Next time we can get up, we'll make sure to lock the door."

—

Tony's heat got worse. He made a nest of their clothes in the middle of the cockpit and ripped the cushions from the seats to add to it. In a feral moment he wasn't particularly proud of, he rolled all over everything to rub his scent in, then pushed Peter into the middle of it and rubbed himself all over Peter, too.

It didn't start out as a sex thing, but it quickly turned that way, Tony's writhing changing into thrusting until he came all over Peter's stomach. Peter rolled them over, held Tony down, and returned the favor.

Peter curled up with him after, and Tony thought, coherency stealing over him once more, _Please, please, keep me_. He had control enough to keep his begging to himself. He buried his face in Peter's shoulder, but he didn't bite down.

—

Peter woke him in the middle of what passed for ship's night—lights dimmed and trying to catch some shut eye on the floor nest—or maybe Tony had woken Peter first, grinding against his thigh. Peter had his hands on Tony's ass and was making encouraging noises. It felt nice, but Tony was also achingly empty. Tony shifted from straddling Peter's thigh to his dick, sliding right on with a wet sound and a feeling of ecstasy.

"Oh," Peter said softly. " _Oh_."

"How are you so perfect?" Tony asked, not expecting an answer, not sure what he wanted. An apology, for being irresistible? A vow he'd be a little less so in future, even if the damage was already done and Tony had long ago passed the point of no return, helplessly adoring, hopelessly in love? Some sort of attempt to make amends? Honestly, Tony felt like this was a pretty good one, Peter rolling them over to thrust lazily into Tony.

It was sleepy, the both of them clumsy with it. Peter snuffled at Tony's shoulder and mumbled, "Come on, come on."

Tony wrapped a hand around himself and let Peter drive him over the edge. He drifted for a while as Peter finished up, thrusting a few more times, and then collapsed on top of Tony like some sort of uncomfortable full body pillow. Peter kissed his neck, gave another sleepy little sound, and fell back asleep, breathing gone heavy and deep once more.

Tony stayed awake, staring at him like a creep, for several hours, until long after Peter had slipped out of him and Tony's need grew too great once more.

"Peter." Tony nudged him. "Pete. Wake up and knot me."

—

"What would you have done if I hadn't been here?" Peter asked. "If you were on Earth, I mean."

"I have a bunch of devices for this very purpose," Tony said as he bounced on Peter's dick, beyond caring that he'd just relegated Peter to the same level as a sex toy. "Nice, quiet toys that wouldn't sass me or follow me onto a spaceship when they were meant to stay safe at home."

"You're so sweet when you're begging for my knot," Peter didn't sound like he minded either way, "but you get really grumpy when you realize I can't give it to you again just yet."

"You're a teenager and you have a healing factor. You've already got it up. How much harder is it to get it in?"

Peter stifled his laughter against Tony's shoulder. It was present in his voice as he said, "It's hard. It's really, really hard."

"You are the worst," Tony said, but it felt like, _I adore you_.

"Tony?" Peter's voice had gone quiet again. It didn't bode well. "You know it's not just the hormones, right?"

"Yeah, kid. I know." There was defeat in Tony's voice. It felt like surrender. Tony sighed. Peter's face remained on his shoulder. Tony hadn't stopped moving. He kept cresting higher, but he wasn't really getting anywhere. "If you still want to—"

"If I want what?"

"I'll have FRIDAY throw out the list." Tony felt Peter's head come up, but Tony had his eyes closed now. "There's—there's only one—"

"If you're saying this because you hope it'll cause me to spontaneously pop a knot—" Peter said warningly, and Tony opened his eyes, made himself meet Peter's painfully hopeful gaze.

"I want you to claim me," Tony said. "I want your mark. I want your teeth in my—fuck."

Peter had only needed a couple affirmations before suiting word to deed, taking what Tony was saying as instruction. It hurt. It was good. It was just enough to finally drive Tony over into glorious freefall.

—

Thor and his friends caught up before the water ran out, a couple days after they'd sent the distress call. Tony was still in heat, Peter was still in rut, and it was probably a good thing everyone else was an alien.

"You smell terrible. Did they not have a sonic shower on this rig?" Rocket asked, never mind that they did and that Peter and Tony had both spent a significant amount of time in there before allowing anyone to come over. "Or do all humans smell this bad?"

"I am Groot," Groot said.

"Yes, I told you. This is unique to their kind," Thor said, "but only rarely does this affliction manifest itself. Give them time, and they'll return to normal."

"I'm so glad I didn't get this with my human half," Quill said.

"Give us food and water and go away," Tony said, stomping hard on the nearly overwhelming urge to attack the interlopers. "Come back in a few days."

Peter made grumbling little growling noises that Tony should not have found as attractive as he did.

"A compromise: come over to our ship where there's a room with a bed and a door with a lock, and we'll leave food and water outside whenever you need it and otherwise pretend you're not here," Gamora said.

"Whoa, whoa, whoa." Rocket held up his tiny little paw hands. "Who's going to give up their room for Feral and Smelly here? _I'm_ not giving up my room."

"I am Groot."

"Yeah, Groot, either."

"Sweet Rabbit, I promise neither of you need be shifted. They wouldn't be able to fit in your bed."

"I don't want to give up my room, either," Quill said.

Tony almost wished they'd been a bit slower catching up.

—

By the time they made it back to Earth, Tony's heat was pretty much over.

"You should knot me one last time." Tony licked at the side of Peter's neck. They'd finished getting dressed, but Tony wanted to strip him naked again. "Just to be sure."

"Just to be sure," Peter echoed.

Quill banged on the door. "Have your weird, freaky sex rituals in your own home! You're being evicted!"

"What do you say, Peter?" Tony grinned. "Want to come home with me for more weird, freaky sex rituals?"

"Yes," Peter said with an eagerness that had failed to be tempered by several days straight of doing that exact thing. "Please."

They went home.

**Author's Note:**

> Content advisories: The dubious consent tag is for the whole A/B/O and mating cycles/in heat thing. There are also brief references to off-screen kidnapping and canon-typical violence, as well as IW events. Also, the usual age gap. Please feel free to ask if you have any questions or special concerns.


End file.
